import javax.management.remote.rmi.RMIConnectionImpl_Stub;
import java.sql.Connection;
import java.util.*;

public class Test {

    int[] dx = {0,0,-1,1};
    int[] dy = {1,-1,0,0};
    int m,n;
    
    
    //为高尔夫比赛砍树
    public int cutOffTree(List<List<Integer>> f){
        m = f.size(); n = f.get(0).size();
        List<int[]> trees =new ArrayList<>();
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                if (f.get(i).get(j) > 1){
                    trees.add(new int[]{i,j});
                }
            }
        }
        Collections.sort(trees,(a,b)->
        {
            return f.get(a[0]).get(a[1]) - f.get(b[0]).get(b[1]);
        });
        int bx = 0, by = 0;
        int ret = 0;
        for (int[] next : trees) {
            int a = next[0], b = next[1];
            int step = bfs(f,bx,by,a,b);
            if (step == -1) return -1;
            ret+= step;
            bx = a; by = b;
        }
        return ret;
    }
    public int bfs(List<List<Integer>> f, int bx,int by,int ex,int ey){
        if (bx== ex && by == ey) return 0;
        
        Queue<int[]> q = new LinkedList<>();
        boolean[][] vis = new boolean[m][n];
        q.add(new int[]{bx,by});
        vis[bx][by] = true;
        
        int step = 0;
        while (!q.isEmpty()){
            int sz = q.size();
            step++;
            while (sz-- != 0){
                int[] t = q.poll();
                int a = t[0], b= t[1];
                for (int i = 0; i < 4; i++) {
                    int x = a+dx[i], y = b+dy[i];
                    if (x>=0 && x<m && y>=0 && y<n && f.get(x).get(y)!=0 && !vis[x][y]){
                        if (x == ex && y == ey) return step;
                        q.add(new int[]{x,y});
                        vis[x][y] = true;
                    }
                }
            }
        }
        return -1;
    }
    
    
    
    //单词接龙
    public int ladderLength(String beginWord, String endWord, List<String> wordList){
        Set<String> hash = new HashSet<>();
        for (String s:wordList) {
            hash.add(s);
        }
        Set<String> vis = new HashSet<>();
        
        if (!hash.contains(endWord)) return 0;
        
        Queue<String> q = new LinkedList<>();
        q.add(beginWord);
        vis.add(beginWord);
        
        int ret = 1;
        while (!q.isEmpty()){
            ret++;
            int sz = q.size();
            while (sz-- != 0){
                String t = q.poll();
                for (int i = 0; i < t.length(); i++) {
                    char[] tmp = t.toCharArray();
                    for (char ch = 'a'; ch < 'z'; ch++){
                        tmp[i] = ch;
                        String next = new String(tmp);
                        if (hash.contains(next) && !vis.contains(next)){
                            if (next.equals(endWord)) return ret;
                            q.add(next);
                            vis.add(next);
                        }
                    }
                }
            }
        }
        return 0;
    }
    
    


    
    //最小基因变化
    public int minMutation(String startGene,String endGene,String[] bank){
        Set<String> vis = new HashSet<>();//用于标记已经搜说过的状态
        Set<String> hash = new HashSet<>();//用于统计基因库里的字符串
        for (String s:bank) {
            hash.add(s);
        }
        char[] change = {'A','C','G','T'};
        
        if (startGene.equals(endGene)) return 0;
        if (!hash.contains(endGene)) return -1;
        
        Queue<String> q = new LinkedList<>();
        q.add(startGene);
        vis.add(startGene);
        int step = 0;
        
        while (!q.isEmpty()){
            step++;
            int sz= q.size();
            
            while (sz-- != 0){
                String t = q.poll();
                for (int i = 0; i < 8; i++) {
                    char[] tmp = t.toCharArray();
                    for (int j = 0; j < 4; j++) {
                        tmp[i] = change[j];
                        String next = new String(tmp);
                        if (hash.contains(next) && !vis.contains(next)){
                            if (next.equals(endGene)) return step;
                            q.add(next);
                            vis.add(next);
                        }
                    }
                }
            }
        }
        return -1;
    }
    
    
    
    
    //迷宫中离入口最近的出口
    public int nearestExit(char[][] maze,int[] e){
        int m = maze.length, n= maze[0].length;
        boolean[][] vis = new boolean[m][n];
        Queue<int[]> q = new LinkedList<>();
        q.add(new int[]{e[0],e[1]});
        vis[e[0]][e[1]] = true;

        int step = 0;

        while (!q.isEmpty()){
            step++;

            int sz = q.size();
            for (int i = 0; i < sz; i++) {
                int[] t = q.poll();
                int a = t[0] , b = t[1];
                for (int j = 0; j < 4; j++) {
                    int x = a+dx[j], y = b+dy[j];
                    if (x>=0 && x<m && y>=0 && y<n && maze[x][y]=='.' && !vis[x][y]){
                        if (x==0 || x==m-1 || y==0 || y==n-1) return step;
                        
                        vis[x][y] = true;
                        q.add(new int[]{x,y});
                    }
                }
            }
        }
        return -1;
    }

}
